The invention pertains to separating devices for separating a mixture of sand and gravel from water for example, when such a mixture is pumped from excavating areas prior to construction of a building in the area. Before such a mixture can be dumped into storm sewers, it must be preconditioned, that is to say the great majority of the solid particles, such as sand and gravel must be removed from the water before it can be conducted to the storm drains. This presents a problem due to the large volume of such a mixture that is pumped from the excavated areas and which must be disposed of in a rapid manner. Such separating devices find particular utility when used in dewatering pump apparatus, such as shown in my U.S. Pat. No. 3,910,728, where such apparatus is used to pump a large volume of water and so-called trash from excavated areas and the mixture is conveyed elsewhere through a large conduit. If such water discharge is to be run into a storm drain, it must first be preconditioned as above noted.
Various separating devices have been attempted to be used, but have generally employed filter media which are subject to fouling and require frequent replacing. Other devices are incapable of handling a large volume of trash mixture, and/or are more or less permanent installations which are difficult to move from one pumping site to another.